Method and apparatus for generating aqueous silica network particles

ABSTRACT

An aqueous composition including silica particles with a particle size distribution and particle structure that improve the water retention and exchange characteristics of the aqueous composition is provided. The aqueous silica composition includes silica network particles and water. The silica network particles comprise main particles and bridging particles that form chains between adjacent main particles. The main particles have a particle size greater than the particle size of the bridging particles. Because of the presence of the silica network particles, the aqueous composition is capable of wetting a hydrophobic substrate more than pure liquid water. The silica network particles are generated in water by a method in which an aqueous sodium silicate solution is subjected to vigorous agitation in air, followed by periods of circulation through magnetic fields of alternating direction and further periodic agitation exposed to the air. An apparatus for carrying out the method is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication No. 60/107,752 filed Nov. 10, 1998.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for formingsilica network particles in water using magnetic treatment and thegradual adsorption of carbon dioxide from air, and also relates to anaqueous composition that includes the silica network particles and canbe used to hydrate body parts such as skin.

The use of magnetic fields to alter the course of chemical reactions inwater has been reported in the scientific literature for some time. Forinstance, in “Experimental Evidence for Effects of Magnetic Fields onMoving Water,” IEEE Transactions on Magnetics, Vol. Mag-21, No. 5,September 1985, pages 2059-2061, Kronenberg reported that passage of awater layer in which a calcium carbonate precipitate was forming alteredthe crystal form (growth habit) of the precipitate; and in U.S. Pat. No.4,888,113, there is disclosed a device including bar magnets placed oneither side of a pipe, which prevents the formation of carbonate scalein the pipes.

It is also reported in the patent literature that an aqueous colloidalsilica can be formed from soluble silicates by repeated passage of thesilicate solution through an appropriately structured magnetic field.For example, U.S. Pat. Nos. 5,658,573, 5,607,667, 5,599,531 and5,537,363 disclose a method and an apparatus for generating a silicatecolloid from a highly alkaline and nonstoichiometric solution of sodiumsilicate using a quadrupole magnetic field. It is reported that themethod and apparatus produce particles from 10 to 100 angstroms in size.These patents also report that the silicate colloid produced using themethod and apparatus can be used as a hydrating agent in body care andhair care compositions.

Generally, hydrating agents are incorporated into skin care products inorder to enable water to penetrate into skin. The skin consists of twolayers: the epidermis, the outer layer, and the dermis, the inner layer.The epidermis is a stratified, squamous epithelial layer whose cellsundergo a process of division and differentiation. The outermost portionof the epidermis is the keratinized stratum corneum. The keratinizationprovides mechanical protection and is also a water barrier. Therefore,it not only helps keep the internal milieu constant and prevents waterloss, but also prevents easy access to the deeper layers byenvironmental products. This physical attribute thus makes it difficultto hydrate the inner layer of the skin when it becomes dry. Accordingly,there have been efforts to prepare a hydrating agent that whenincorporated into a skin care composition allows the composition tohydrate the skin faster and more easily than bulk water.

Although it is reported in U.S. Pat. Nos. 5,658,573, 5,607,667,5,599,531 and 5,537,363 that the colloidal silica prepared by thedisclosed methods satisfies the need for a hydrating agent that willenable water to penetrate skin, it is believed the colloidal silicadisclosed in these patents does not provide an optimum solution to theproblem of inadequate hydrating action in skin care products.Specifically, the particle size distribution and the particle structureof the colloidal silica in the aqueous composition in U.S. Pat. Nos.5,658,573, 5,607,667, 5,599,531 and 5,537,363 significantly limit: (1)the water retention and exchange characteristics of the colloid; (2) theextent of interaction of absorbed water on the colloidal silica; (3) theinteraction of an aqueous composition including the colloid with ahydrophobic substrate; and (4) the wetting properties of an aqueouscomposition including the colloid on a hydrophobic substrate.

Accordingly, there is a need for an silica composition with a particlesize distribution and particle structure that improves the waterretention and exchange characteristics of an aqueous compositionincluding the silica composition. In addition, there is a need for anaqueous silica composition that has improved wetting characteristicswhen interacting with a hydrophobic substrate.

BRIEF SUMMARY OF THE INVENTION

The foregoing needs are satisfied by aqueous silica network particleswith unusual water retention and exchange properties. The silica networkparticles are generated in water by a method in which an aqueous sodiumsilicate solution is subjected to vigorous agitation in air, followed byperiods of circulation through magnetic fields of alternating directionand further periodic agitation exposed to the air. The incorporation ofcarbon dioxide from the air occurs in both stages of agitation in thisprocess. The result, at the end of the method, is aqueous silicaparticles with unique network morphology. The term “network” as usedherein describes a morphology wherein bridging particles form chainsbetween main particles. This network morphology can also be described asa three dimensional mesh-like structure. With this network morphology,fluid regions are contained within the network. In one version of theinvention, the aqueous silica network particles have a structurecomprising bridging particles that form chains between adjacent mainparticles, wherein the main particles have a particle size greater thanthe bridging particles. An aqueous composition having the silica networkparticles has a lower interaction energy with hydrophobic materials thanbulk water, and when added to a typical skin care preparation, enhancesthe exchange of water with the layers of skin.

Without intending to be bound by theory, it is believed that when thesilica network particles are present in an aqueous composition, thenetwork of each particle surrounds and encloses layers of bound waterwith a structure appreciably different from that of bulk water. It isbelieved that the alternating magnetic field used in generating thesilica network particles serves to change the rate at which stableaggregates of water molecules form around other molecules or ions, whichin turn alters the aggregation kinetics of the silica to produce thenetwork particle morphology. In the normal polymerization of silicatesolutions, a variety of particle sizes are formed, but a form of Ostwaldripening predominates wherein bigger particles grow at the expense ofsmaller particles. In contrast, the silica in the present inventionforms the aforementioned network particle structure. It is furtherbelieved that the unusual properties of the silica network particles ofthe present invention are due to the gradual lowering of pH as carbondioxide is absorbed, favoring chain formation over particle growth, andthe stabilization of water clathrate-like structures around molecularcarbon dioxide that absorb on the surface of larger but not smallerparticles favoring the formation of chains of smaller particles. Theresult is silica network particles in water with an unusual physicalreactivity to liquid water.

An aqueous composition of the silica network particles can bebeneficially used as a hydrating agent in a wide variety of body carecompositions, such as shampoos, conditioners, styling gels, stylingmists, hair coloring preparations, body lotions, face creams, skincreams, bath additives, pedicure and manicure applications, handlotions, lip balms, mouthwashes, toothpaste, lipsticks, suntan lotions,and sunscreen lotions. The use of an aqueous composition including thesilica network particles in facial cleansers, moisturizing creams, andfacial mists provides a package for improvement of skin and mucusmembrane moisture, tone, and youthful appearance.

It is therefore an object of the present invention to provide an aqueouscomposition including silica particles that have a particle sizedistribution and particle structure that improve the water retention andexchange characteristics of an aqueous composition including the silicaparticles.

It is another object of the present invention to provide an aqueoussilica composition that has improved wetting characteristics wheninteracting with a hydrophobic substrate.

It is a further object of the present invention to provide a body carecomposition that has improved hydration characteristics when compared toknown body care compositions.

It is still another object of the present invention to provide a methodfor forming an aqueous composition including silica particles that havea particle size distribution and particle structure that improve thewater retention and exchange characteristics of an aqueous compositionincluding the silica particles.

It is yet another object of the present invention to provide anapparatus for forming an aqueous composition including silica particlesthat have a particle size distribution and particle structure thatimprove the water retention and exchange characteristics of an aqueouscomposition including the silica particles.

These and other objects, advantages and aspects of the invention willbecome apparent from the following description. In the description,reference is made to the accompanying drawings which form a part hereof,and in which there is shown a preferred embodiment of the invention.Such embodiment does not necessarily represent the full scope of theinvention and reference is made therefore, to the claims herein forinterpreting the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an apparatus in accordance with the presentinvention for preparing the aqueous silica network particles of thepresent invention;

FIG. 2 is a top view of the magnetic generating unit of the apparatus ofthe present invention taken along line 2—2 of FIG. 1;

FIG. 3 is a cross-sectional view of the magnetic generating unit shownin FIG. 2 taken along line 3—3 of FIG. 2;

FIG. 4 is a top view of an alternative magnetic generating unit of theapparatus of the present invention taken along line 2—2 of FIG. 1;

FIG. 5 is a cross-sectional view of the magnetic generating unit shownin FIG. 4 taken along line 5—5 of FIG. 4;

FIG. 6a is a photomicrograph taken with an Environmental ScanningElectron Microscope at a magnification of 3125× of a silica networkparticle after a first stage of processing in accordance with thepresent invention;

FIG. 6b is a photomicrograph taken with an Environmental ScanningElectron Microscope at a magnification of 25000× of a silica networkparticle after a first stage of processing in accordance with thepresent invention;

FIG. 7 is a photomicrograph taken with an Environmental ScanningElectron Microscope at a magnification of 25000× of a silica networkparticle after complete processing in accordance with the presentinvention;

FIG. 8 is a photomicrograph taken with an Environmental ScanningElectron Microscope at a magnification of 3200× of a silica networkparticle after complete processing in accordance with the presentinvention;

FIG. 9 is a photomicrograph taken with an Environmental ScanningElectron Microscope at a magnification of 4000× of a silica networkparticle after complete processing in accordance with the presentinvention and after freezing the particle with liquid nitrogen;

FIG. 10 is a photomicrograph taken with an Environmental ScanningElectron Microscope at a magnification of 1650× of a silica networkparticle after complete processing in accordance with the presentinvention and after freezing the particle with liquid nitrogen; and

FIG. 11 is a photomicrograph taken with an Environmental ScanningElectron Microscope at a magnification of 4600× of a silica networkparticle after complete processing in accordance with the presentinvention and after freezing the particle with liquid nitrogen.

DETAILED DESCRIPTION OF THE INVENTION

An aqueous silica composition in accordance with the present inventionincludes silica network particles and water. The silica networkparticles comprise main particles and bridging particles that formchains between adjacent main particles. The main particles have aparticle size greater than the particle size of the bridging particles.Preferably, the silica network particles have a particle diametergreater than or equal to 1000 nanometers, and most preferably, thesilica network particles have a particle diameter greater than or equalto 3000 nanometers. The silica network particles are heterodisperse asdetermined by zeta potential measurements. Preferably, the mainparticles and the bridging particles have a substantially spheroidshape, and form a three dimensional structure. Preferably, the aqueoussilica composition has a carbonate concentration (carbonic acid plusbicarbonate ion plus carbonate ion) of about 4 to about 8 millimoles perliter after preparation. The aqueous silica composition is capable ofwetting a hydrophobic substrate more than pure liquid water.

The aqueous silica network particles of the present invention areprepared by dissolving sodium metasilicate pentahydrate (Na₂SiO₃.5H₂O)in distilled water in an open-air mixing chamber to produce a solution.The solution is then subjected to constant agitation by an agitator.Preferably, the amount of sodium metasilicate pentahydrate added to thewater is such as to prepare a solution having about 100 parts permillion to about 500 parts per million, and preferably 300 parts permillion, in silica before any further processing. No further dilution ofthe silicate solution is required. The silicate/water mixture isagitated while exposed to the open air at room temperature for a periodof time. The agitation results in the formation of some sodium carbonateand sodium bicarbonate through absorption of carbon dioxide from theair. The pH of the solution after the initial agitation (which willoften be referred to hereinafter as “Stage 1 Material”) is preferablyabout 9.5 to about 10.5.

The solution (“Stage 1 Material”) is then pumped repeatedly throughnonmagnetic helical tubing which passes repeatedly past the pole facesof magnets arranged so that the South and North pole faces alternate insuccession so that the solution experiences a repeated change in fielddirection. After passing through the tubing, the solution passes into amixing vessel where it is subjected to further agitation in contact withair. The solution is repeatedly recirculated through the tubing and themixing vessel. After processing, the solution (which will often bereferred to hereinafter as “Stage 2 Material”) is removed and stored innon-glass containers. The pH of the Stage 2 Material after processing ispreferably about 8.5 to about 9.5.

A solution treatment apparatus 10 which has been found advantageous forpreparing the aqueous silica network particles of the present inventionis shown in FIGS. 1-5. As shown, an open-air mixing vessel 12 is securedto a frame 14. A variable speed electric motor 15, which is capable ofoperating at speeds of 1750-2500 rpm, is also secured to the frame 14. Ashaft 16 extends from the motor 15 to support a 2 inch serrated cowl'sshearing blade 17 in the mixing vessel 12. The mixing vessel 12 and themotor 15 are positioned such that a solution in the mixing vessel 12 issubject to agitation by the shearing blade 17 off the central verticalaxis of the mixing vessel 12.

A positive displacement pump 25 is also secured to the frame 14. Thepump 25 is fully adjustable so that a desired volume flow rate and pumppressure can be achieved. The inlet of the pump 25 is placed in fluidcommunication with the mixing vessel 12 by way of a vessel outputconduit 18. The vessel output conduit 18 is preferably a non-magneticstainless steel tube. An inlet 26 of the vessel output conduit 18 isaccurately positioned in the mixing vessel 12 such that only adequatelyaerated solution is drawn into the pump 25. The outlet of the pump 25 isplaced in fluid communication with a magnetic field generating unit,indicated generally at 30, by way of a pump output conduit 32.

The magnetic field generating unit 30, best shown in FIGS. 2 and 3, is afreestanding unit that allows a solution to repeatedly pass through analternating magnetic field. The magnetic field generating unit 30includes an outer cylindrical carbon steel tubular wall 34 which ismounted on a frame 36. The tubular wall 34 is preferably made from asheet of ferromagnetic material to add an additional magnetic imagefield to the magnetic field generating unit 30. Fluorocarbon linednon-magnetic tubing 38 is wrapped into a helical coil along the innersurface of the tubular wall 34. The tubing 38 extends from a top portionof the tubular wall 34 to a bottom portion of the tubular wall 34.Preferably, the tubing 38 is a non-ferrous tubing sold under thetrademark “Tygon” by Dupont, Dover, Del., USA. In one version of themagnetic generating unit 30, the tubing 38 is approximately fifty feetlong and has a ½ inch inside diameter. The solution to be treated isreceived by the tubing 38 by way of the pump output conduit 32 which isin fluid communication with the pump 25.

The magnetic field generating unit 30 also includes vertical columns ofevenly spaced magnets 40 that are positioned inside an inner cylindricaldrum 42 made from iron or other ferromagnetic material to take advantageof a magnetic image field which adds to the magnetic field intensity.The inner cylindrical drum 42 is positioned inside the helical coiledtubing 38. The magnets 40 are held in position by the inner drum 42 andare separated from each other by vertical foam non-magnetic insulationcolumns 44. The magnets 40 are arranged such that the poles of adjacentmagnets are of opposite orientation, i.e., the North (“+”) pole of onemagnet faces the tubing 38 and the South (“−”) pole of the adjacent twomagnets faces the tubing 38. In a preferred version of the magneticgenerating unit 30, the pole faces of the magnets 40 arranged so thatthe South and the North pole faces alternate in succession withapproximately 1 inch between centers.

With this arrangement of the magnets 40, the solution moving through thetubing 38 experiences a constantly changing magnetic field every inchwhile in the magnetic field generating unit 30. As particles in asolution flow through the tubing 38, they cut through the lines ofmagnetic flux of the magnetic field generated by the magnets 40, i.e.,the direction of fluid flow through the tubing 38 is at right angles tothe magnetic field.direction. It is preferred that all of the magnets 40be identical, except for their pole orientation, and that they eachproduce approximately equal magnetic flux. Preferably, the magneticfield strength is approximately 1,000 Gauss (0.1 Tesla) at the pole faceof the individual magnets 40 and the magnetic field is calculated toremain stronger than 500 Gauss throughout the ferromagnetic enclosedconfiguration of the magnetic generating unit 30. Preferably, themagnets 40 are permanent magnets. Alternatively, the magnets 40 may beelectromagnets powered by a D.C. power supply. Further, paramagneticions be added to enhance the formation of the material.

In another version of the invention, the solution treatment apparatus 10has an magnetic field generating unit 30 a, shown in FIGS. 4 and 5, thatincludes a second group of vertical columns of evenly spaced magnets 50that are positioned outside the tubular wall 34. The magnets 50 arepositioned inside an outer cylindrical drum 52 made from iron or otherferromagnetic material to take advantage of a magnetic image field whichadds to the magnetic field intensity. The outer cylindrical drum 52 andthe magnets 50 are positioned outside the tubular wall 34 and thehelical coiled tubing 38. The magnets 50 are held in position by theouter drum 52 and are separated from each other by vertical non-magneticinsulation columns 54. The magnets 50 are arranged such that the polesof adjacent magnets are of opposite orientation, i.e., the North (“+”)pole of one magnet faces the tubing 38 and the South (“−”) pole of theadjacent two magnets faces the tubing 38.

The solution treatment apparatus 10 can be used to treat a solution asfollows. A solution to be treated is added to the open-air mixing vessel12. The variable speed electric motor 15 is activated and preferably isset to operate at a speed of 1750-2500 rpm. The solution in the mixingvessel 12 is then subject to agitation by the shearing blade 17 at aposition off the central vertical axis of the mixing vessel 12. Aftersufficient agitation and aeration of the solution, the pump 25 pumps thesolution from the mixing vessel 12 by way of the vessel output conduit18. As noted above, the inlet 26 of the vessel output conduit 18 isaccurately positioned in the mixing vessel 12 such that only adequatelyaerated solution is drawn into the pump 25. The pump 25 pumps thesolution through the pump output conduit 32 and into the helical coiledtubing 38 in the magnetic field generating unit 30. After the solutionto be treated has circulated through the tubing 38 in the magneticgenerating unit 30, it is then returned to the mixing vessel 12 by wayof a magnetic generating unit output conduit 60 which is in fluidcommunication with the tubing 38 and the mixing vessel 12. In the mixingvessel 12, the solution is again subjected to agitation and aeration bythe shearing blade 17, and the circulation process occurs again, i.e.,the solution is pumped from the mixing vessel 12, through the tubing 38in the magnetic generating unit 30 and returned to the mixing vessel 12.The recirculation through the mixing vessel 12 and the tubing 38 isrepeated for a predetermined time period, after which the pump 25 andthe motor 15 are turned off and the treated solution is removed from themixing vessel 12.

Improved body care compositions can be formulated by adding an aqueouscomposition including the aqueous silica network particles of thepresent invention to an existing body care composition such as a skincream, body lotion, shampoo, hair conditioner, cleanser, etc. to bringthe concentration of the silica network particles within the body carecomposition to a preferred range of from about 1 parts per million toabout 50 parts per million. The body care composition is then used in anormal manner. The presence of the silica network particles of thepresent invention in the body care composition increases the ability ofthe composition to penetrate into body parts. When incorporating theaqueous silica network particles into skin care products, it is believedthat the presence of aqueous silica network particles allows the waterin the product to penetrate more deeply into the deeper layers of theepidermis.

The invention is illustrated further in the following Examples which areexemplary in nature and are not intended to be limiting.

EXAMPLE 1

Silica network particles in water in accordance with the presentinvention were prepared as follows. A 45.6 gram sample of commercialgrade sodium metasilicate pentahydrate (Na₂SiO_(2.5)H₂O, available fromSigma Chemical, St. Louis, Mo., USA) was dissolved in 15 gallons (56,700grams) of distilled water in a non-metallic, thirty-gallon containerwith a conical bottom at a room temperature of approximately 20 degreesCelsius. The sodium metasilicate solution was then placed in athirty-gallon polyethylene, cylindrical tank having a diameter of 18inches and a depth of 35 inches. The solution was then mixed with astainless steel dispersion blade having a diameter of 6 inches. Thedispersion blade was designed to shear the solution by incorporatinglarge multi-it angled “teeth” in its design. The blade was mounted on anaxis approximately 10 degrees from the tank centerline, which served toincrease the shearing action of the blade. A 0.5 inch diameter stainlesssteel shaft was used to attach the blade to a 1.5 horsepower, variablespeed electric motor which rotated the blade at an average speed ofbetween 1750 and 2500 rpm. The solution was agitated using thedispersion blade for 2½ hours. At the end of the agitation time, the pHof the solution (Stage 1 Material) as measured with a calibrated glasspH electrode (available from Fisher Scientific, Philadelphia, Penn.,USA) was 9.5-10.5.

The Stage 1 Material was then removed from the thirty-gallon containerafter processing and one gallon of the Stage 1 Material was added to themixing vessel 12 of the solution treatment apparatus 10 described above.The solution was agitated and aerated in the mixing vessel 12 and pumpedthrough approximately fifty feet of ½ inch inside diameter “Tygon” brandtubing that coiled around vertical columns of evenly spaced magnets asdescribed above in the description of the solution treatment apparatus10. The pump rate and quantity of Stage 1 Material was selected suchthat in four hours of operation of the pump and the motor of thesolution treatment apparatus, the Stage 1 Material passed 360 timesthrough the tubing. After processing, the solution (the “Stage 2Material”) is removed and stored in a non-glass containers. The pH ofthe Stage 2 Material was determined to be 8.5-9.5 as measured with acalibrated glass pH electrode. It was colorless and free of visibleparticulate matter and had an electrical conductivity between 0.65 and0.75 mS/cm. The Stage 2 Material is completely miscible in water,ethanol, methanol, isopropanol, and acetonitrile.

Analysis of the Aqueous Silica Network Particles Prepared in Example 1

a. Light Scattering Analysis

In order to determine the structure and the particle size distributionof the aqueous silica network particles prepared in Example 1, samplesof the material prepared in Example 1 were analyzed using a lightscattering apparatus. Specifically, light scattering studies wereconducted using a Coulter-Beckman DELSA 440 apparatus, which allowsmeasurements to be made in two different modes: a size determinationmode and a zeta-potential/electrical mobility mode. This particularapparatus works by analyzing light scattered from four sub-beams of anoriginal helium-neon laser beam, sent at different angles through thematerial to be studied. To avoid multiple scattering effects, the beamgeometry is such that the scattering volume is small, from 0.01 to 0.03microliters.

Samples of the material prepared in Example 1 were analyzed using thesize determination mode of the light scattering apparatus. A majority ofthe analyses using the size determination mode indicated particle sizesin excess of 3000 nanometers. Scattering by smaller particles appearedonly in a fraction of the measurements made with the instrument.Specifically, 85 percent of the size determination runs showed particlesof size greater than 3000 nanometers.

Samples of the material prepared in Example 1 were then analyzed usingthe zeta-potential/electrical mobility mode of the light scatteringapparatus. When using the zeta-potential/electrical mobility mode, ahomodisperse material typically generates experimental data showing asingle value of the zeta potential. However, when samples of thematerial prepared in Example 1 were analyzed using thezeta-potential/electrical mobility mode of the light scatteringapparatus, several groupings of zeta potential measurements occurred atroughly −12, −25 and −39 mV. After ten repetitions of the zeta potentialmeasurement on at least two samples of the material prepared in Example1, more than 50% of the samplings showed a zeta-potential value morenegative than −10 mV. Therefore, it can be concluded that the materialprepared in Example 1 was heterodisperse. Upon plotting of the halfwidth of the observed peaks against scattering angle, it was confirmedthe material prepared in Example 1 was heterodisperse.

b. Electron Microscopy Analysis

In order to determine the structure and the particle size distributionof the aqueous silica network particles prepared in Example 1, samplesof the material prepared in Example 1 were analyzed using TransmissionElectron Microscopy and Environmental Scanning Electron Microscopy.

First, Transmission Electron Microscopy (TEM) was used to characterizethe particle size distribution of: (1) a sample of the silica networkparticles of Example 1 after the initial agitation step (Stage 1Material), and (2) a sample of the silica network particles in water ofExample 1 after complete processing in accordance with the methods andapparatus of Example 1 (Stage 2 Material). It was determined that theparticle size distribution differed between Stage 1 Material and Stage 2Material, when dried completely under vacuum. Unexpectedly, the viewingof all these micrographs suggested a ramifying, beads on a string model,for the structure of the Stage 2 material. In other words, the silicanetwork particle structure comprised bridging particles that formedchains between adjacent main particles, and the main particles had aparticle size greater than the bridging particles. Many of themicrographs of the Stage 2 material suggested a superstructure of theseramifying beads-on-a-string resembling a collapsed three-dimensionalball of chicken wire. Smaller versions of this structure were seen onmicrographs of the Stage 1 material.

Second, Environmental Scanning Electron Microscopy (ESEM) was used tofurther determine the structure and the particle size distribution ofthe aqueous silica network particles prepared in Example 1. ESEM hasproven to be quite advantageous in certain materials characterizationanalyzes as the material being analyzed can be viewed directly in itsnative state. For instance, in ESEM, no sample preparation is needed(although the atmosphere within the sample chamber must be controlled)and water does not have to be excluded from the materials sample beinganalyzed. A sample in its native state is placed on the sample stage inthe vacuum chamber of an ESEM. The chamber is slowly evacuated whilemaintaining a water vapor pressure of about 6.6 torr and 100% relativehumidity in the chamber. Samples can be allowed to dry down byevaporation of the water in the sample.

The above ESEM procedure was applied to a sample of Stage 1 Material inits native state. The structure observed was when the water present inits native state vaporized. As seen in FIGS. 6a and 6 b, the structureobserved consisted of stacks of many small plates that ramify throughoutthe sample. Multiple sharp points were exhibited in this structure whichis consistent with an underlying tetrahedral base unit for the material.A multitude of jumbled stacked plates were evident in highermagnification views, which is suggestive of the structure of graphite,although the Stage 1 material was much more irregular than graphite.

When identical ESEM processing was used with the Stage 2 Material in itsnative state, a very different structure was revealed and is shown inFIGS. 7 and 8. As in the Stage 1 Material, there was observed aramifying interconnected structure. However, the Stage 2 Material iscomposed of a multitude of irregular spheroids joined to each other. TheStage 2 Material also has rounded soft edges and appears like a berrypudding as best seen in FIG. 8.

During the initial drying down of the Stage 2 material in the ESEMchamber, crystals, presumably of a carbonate, formed evanescently on thesurface of the silica network. In fact, at the drying front of a drop ofthe Stage 2 Material, lower magnification revealed extensive carbonatecrystals appearing through a water film (the ESEM visualizes water asessentially opaque) obscuring the structure of the Stage 2 Material (SeeFIG. 8.). These carbonate structures were 6-10 micrometers in diameter.

When the relative humidity of the ESEM sample chamber was reduced tobelow about 30%, the Stage 1 Material dried in about two minutes. Whenthe same reduction in relative humidity was done with Stage 2 Material,it took about 30 minutes to dry. Clearly, the water retaining capacityof Stage 2 Material was remarkably better than for the Stage 1 Material.In other words, the water retaining capacity of the Stage 2 Material,which was treated in the magnetic field, was improved in relation to theStage 1 Material, which was not treated in the magnetic field.

Third, another ESEM procedure was used to further determine thestructure and the particle size distribution of the aqueous silicanetwork prepared in Example 1. In this procedure, samples prepared inExample 1 were analyzed using analysis technology that involved thefreezing of samples at the temperature of liquid nitrogen and thetransfer of these samples to a sample stage that maintained the samplesat the temperature of liquid nitrogen and then allowed for thecontrolled warming of the sample stage. After processing, samples intheir frozen native state were allowed to warm slowly to about thetemperature of dry ice. The procedure allowed the observer tocontinuously monitor what happened on the sample stage during the slowwarming process. In effect, the sample was allowed to self-etch duringthe warming period revealing the structure within the frozen watermatrix.

Using this ESEM technique, the Stage 1 Material was revealed to have acomplex ramifying structure. As in the unfrozen sample of Stage 1material previously discussed, the structure consisted of many jumbledstacks of plates with sharp edges fused together in a ramifying array.In contrast, the Stage 2 Material as shown in FIGS. 9, 10 and 11,revealed as a complex ramifying system of apparent strings. The materialclearly ramifies in three-dimensions as shown in FIG. 10. At highermagnification levels as in FIG. 11, these strings appeared to be made ofvery small bead-like units fused together to form a complex array ofstrings.

c. Contact Angle Analysis

In order to determine the extent to which the aqueous silica networkparticles of the present invention act as a wetting agent (i.e., asurface-active agent that, when added to water, causes it to penetratemore easily, or to spread over the surface of, another material), acontact angle analysis was performed on the aqueous compositionincluding silica network particles prepared in Example 1. Contact anglemeasurements were taken using a “Tantec” brand Model CAM-PLUS contactangle meter for distilled water (a control), freshly dissolved sodiummetasilicate (another control), a sample of the silica solution ofExample 1 after the initial agitation step (Stage 1 Material), and asample of the silica network particles in water of Example 1 aftercomplete processing in accordance with the methods and apparatus ofExample 1 (Stage 2 Material). Contact angle measurements for these fourmaterials were taken on: (1) glass, (2) Parafilm® brand moisture proof,self-sealing wrapper material commonly used in chemical laboratories,and (3) Teflon® brand tetrafluoroethylene film. The results are givenbelow in Table 1.

TABLE 1 Contact Angle Measurements (in degrees) Materials Tested SodiumStage 1 Stage 2 Metasilicate Material Material Substrate Water Solution(Example 1) (Example 1) Glass 24.5 21.1 26.8 25.4 Parafilm ® film 99.199.4 100.8 95.4 Teflon ® film 104.6 103.5 103.2 98.8

Looking at the results of the contact angle measurements in Table 1, itcan be seen that the contact angle for sodium metasilicate solution onglass is somewhat lower than that for distilled water, but, that forboth Stage 1 Material and Stage 2 Material, the contact angle is greaterthan that for distilled water. On the other hand, the contact angle asmeasured on Parafilm® brand film and Teflon® brand film, which are bothhighly hydrophobic substrates, is significantly reduced for the Stage 2Material. These observations are consistent with the notion that theabsorbed water on the silica network particles has a modified structurethat interacts more favorably with a hydrophobic substrate than that ofbulk distilled water.

If the liquid-vapor surface tension of a liquid is known, and itscontact angle with a solid is measured, then the solid-vapor andsolid-liquid surface tension can be computed using the equations ofstate devised by Newman, et al. (see Separation and PurificationMethods, 9, 69-183, 1980 and J. Colloid. Interface Sci., 49, 291, 1974)and known to those skilled in the art. Using the results of the contactangle measurements reported in Table 1, surface tension computationswere made and are reported in Table 2 below.

TABLE 2 Surface Tension (in mN/m) Materials Tested Sodium Stage 1 Stage2 Metasilicate Material Material Substrate Water Solution (Example 1)(Example 1) Glass 66.1 67.5 65.1 65.7 Parafilm ® film 22.9 22.6 21.726.1 Teflon ® film 19.4 20.1 20.3 23.0

For a composite material, the liquid vapor surface tension is somewhattime dependent. Assuming a surface tension equal to that of water yieldsthe solid-vapor and solid-liquid surface tensions reported in Table 2,it is noteworthy that the solid-vapor tension, or equivalently, thespecific interfacial energy is about 10% reduced for the Stage 2Material on Teflon® brand film, again indicating a more favorableinteraction with a hydrophobic substrate.

d. Titration

It was contemplated that the gradual dissolution and chemical reactionof the sodium metasilicate solution with the carbon dioxide in air is animportant step in the formation of the silica network particles of thepresent invention. In order to determine the extent to which thecarbonates are incorporated into the aqueous silica network particles ofthe present invention, a titration analysis was performed on the aqueoussilica network particles prepared in Example 1. An algorithm wasdeveloped to fit the titration curve of a 10 milliliter sample of theaqueous silica network particles diluted with an equal amount of waterto a theoretical expression based on the published ionization constantsof silicic acid Si(OH)₄ (K₁=2×10⁻¹⁰, K₂=K₃=K₄=2×10⁻¹²) and carbonic acid(K₁=3×10⁻⁷, K₂=5.86×10⁻¹¹). As a result, it was possible to fit thetitration data for the aqueous silica network particles prepared inExample 1 with a standard deviation of less than 0.2 milliliters. Whenthe aqueous compositions including silica network particles prepared inExample 1 was titrated with 0.01N HCl and the best fit parameters, atotal carbonate (carbonic acid plus bicarbonate ion plus carbonate ion)concentration of between 5.5 and 7.2 millimoles per liter wasdetermined.

EXAMPLE 2

An aqueous composition including silica network particles prepared inaccordance with Example 1 was incorporated into cosmetic formulations.The product was tested in three variations, in double-blinded studies.The only difference in the tested variations was the presence or absenceof the aqueous composition of the present invention. The objective wasto determine if the aqueous composition including silica networkparticles improved the hydration of the skin, decreased fine wrinklelines, and enhanced skin tone. The study population age range was 20-65.

The three formulations were sent to 8 cities in the United States to seehow well the formulations performed in the various climates and subjectto a variety of different environmental factors. A number of differentcities were chosen because cosmetic and especially skin care products donot perform equally well in different climates or where different typesof tap water are used. The eight cities were Philadelphia, Portland,Houston. Omaha, Atlanta, Los Angeles, San Diego and Memphis. Salons wereselected in these cities to conduct these clinical trials based on theirbackground in product development and comparison testing. A total of1500 participants were tested in the eight cities listed and 1372 of theparticipants completed evaluations (91%). Side by side comparisons with½ of the subject's face treated with a typical product and ½ with aproduct incorporating the aqueous composition of the present invention.The products were prepared as a cleanser, hydrating mist, hydrating gel,surface active cream, and lotion. A pre-interview and a post-interviewwere conducted with each participant, and the interviews included thefollowing questions: (1) Do you see different results in the hydrationof your skin—if so, what?; (2) Is this product better than, or as goodas, what you are currently using?; (3) What results appear to bespecific to our formulation?; (4) Would you buy this product?; and (5)Did you experience greater hydration, and if so, how long did it seem tolast?. After three months, the data from the study were collated, and itwas determined that: (1) 83% of subjects liked our formulation betterthan or as well as what they had been using; (2) 12% of subjects did notlike our formulation; (3) 5% of subjects did not have an opinion; and(4) 71% of subjects thought they saw fewer fine lines and wrinkles andbetter skin tone after using the cosmetic formulation having the aqueouscomposition including silica network particles prepared in accordancewith Example 1.

Clearly, when the aqueous composition including silica network particlesof the present invention is applied in combination with standardcosmetic ingredients, the result is an increased moisturization of theskin. When the aqueous composition including silica network particles ofthe present invention is utilized as a hydrating agent with additionalcosmetic agents, results show a very high acceptance rate and preferenceby men and women.

EXAMPLE 3

When certain participants in the study described in Example 2 reportedrapid relief from minor burns (e.g., sunburn) and irritation (e.g., fromhot peppers), a systematic study was conducted on the use of certainformulations incorporating the aqueous composition of the presentinvention on individuals recovering from severe burns and surgicalprocedures. The studies in burn patients were undertaken to see if theproduct in the form of a hydrating gel or mist could decrease itching inhealed areas of partial thickness injury or healed grafted regions.These areas often show dryness that tends to clinically correlate withtheir pruritus. Hydrating agents have been used topically to helpdecrease the itching. The multi-center Institutional Review Boardapproved study collected twenty evaluable patients, sixteen of thesefelt the product alleviated itching and hydrated their skin better thana widely used mineral oil based topical agent.

EXAMPLE 4

Patients who undergo laser resurfacing of their skin often experienceprolonged redness that decreases the acceptance of the resurfacing.Topical vitamin C has been shown to help decrease this rednesspostoperatively, but is usually painful on application. In order todetermine if the aqueous composition including silica network particlesof the present invention can reduce the discomfort of individualsundergoing laser resurfacing, a study was conducted. Five hundred (500)milligrams per 100 milliliters (0.5 grams percent) of Ester-C® brandvitamin C was combined with the aqueous composition including silicanetwork particles of the present invention. After application to laserresurfacing patients to reduce the discomfort of laser resurfacing,seven of eight patients were evaluated by digital photography and coloranalysis, and a 25% reduction in time to healing to preoperative coloroccurred with the vitamin C product having the aqueous compositionincluding silica network particles of the present invention compared tostandard post-laser treatment. There was evidence of an overallimprovement in hydration in these patients and an improvement in thedelivery of vitamin C to the skin. There was also a 25% reduction inredness in these patients.

EXAMPLE 5

Additional studies were performed on fibroblast cultures in vitro andshowed a statistically significant reduction in metalloproteases and inthe activity of metalloprotease I and II. When the aqueous compositionincluding silica network particles of the present invention was appliedto the culture. This finding has significant importance in diseaseprocesses in which an imbalance of metalloproteases and tissueinhibitors of metalloproteases, exists.

EXAMPLE 6

A study was performed on radiation therapy patients having damaged skin.It was determined from the study that no harmful effects occurred on thedamaged skin of these patients when the damaged skin was contacted withthe aqueous composition including silica network particles of thepresent invention.

From Examples 1-6, it can be seen that the aqueous composition includingsilica network particles of the present invention provides a base thatis a superior vehicle in transporting water and other compositions intothe skin. The composition of the present invention exchanges water morereadily with healthy or damaged skin than does bulk water and enhancesthe effectiveness of a wide variety of cosmetic preparations as gaugedby clinical trials. It is evident that agents incorporating the aqueouscomposition of the present invention lead to better skin hydration inthe majority of the subjects compared to similar agents without theaqueous composition of the present invention. The composition alsoprovides improved skin hydration and reduces fine wrinkles and enhancesskin tone when incorporated into a skin care composition. Whenincorporated into a body care composition, the composition of thepresent invention is effective in enhancing the quality of the skin andthus is: (1) a skin treating compound, (2) an enhancer of other skintreatment agents, (3) a carrier, and (4) a cosmetic additive.

The aqueous composition of the present invention can effectively deliverother antioxidants beyond the stratum corneum. Products including theaqueous composition of the present invention have been used in a mist,gel, lotion and cream base, each form demonstrating its effectiveness.Products including the aqueous composition of the present invention arewell tolerated and hydrate the skin successfully by allowing moisture topenetrate the skin. This is in contrast to prior compositions in whichhydrophobic materials are transported into the skin to block moistureloss.

There has also been successful demonstration of a formulation having theaqueous composition of the present invention as a hair conditioner.Studies indicate increased absorption through the hair and increasedstrength of hair strands.

It should be understood that the methods and apparatuses described aboveare only exemplary and do not limit the scope of the invention, and thatvarious modifications could be made by those skilled in the art thatwould fall under the scope of the invention. To apprise the public ofthe scope of this invention, the following claims are made.

What is claimed is:
 1. A method of generating silica network particlesin water, the method comprising the steps of: (a) dissolving sodiumsilicate in water to form a solution; (b) agitating the solution; (c)thereafter circulating the solution through an alternating magneticfield greater than the earth's magnetic field; (d) thereafter agitatingthe solution; (e) thereafter circulating the solution through thealternating magnetic field; and (f) repeating steps (d) and (e) aplurality of times until silica network particles are formed in thesolution, wherein step (c) comprises circulating the solution through ahelical coil around vertical columns of evenly spaced magnets creatingan alternating magnetic field.
 2. The method of claim 1 wherein: step(a) comprises dissolving sodium metasilicate pentahydrate in water toform the solution.
 3. The method of claim 1 wherein: step (a) comprisesdissolving sodium silicate in water to form the solution, the solutionhaving from about 100 parts per million silica to about 500 parts permillion silica.
 4. The method of claim 1 wherein: step (b) comprisesshearing the solution with a blade.
 5. The method of claim 1 wherein:step (b) comprises agitating the solution in an open-air mixing chamberuntil the solution absorbs sufficient carbon dioxide to lower the pH tobetween about 9.5 and about 10.5.
 6. The method of claim 1 wherein: step(f) comprises repeating steps (d) and (e) a plurality of times until thesolution absorbs sufficient carbon dioxide to lower the pH to betweenabout 8.5 and about 9.5.
 7. The method of claim 1 wherein: step (d)comprises shearing the solution with a blade in an open-air mixingvessel.
 8. The method of claim 1 wherein: step (f) comprises repeatingsteps (d) and (e) a plurality of times until silica network particlesare formed in the solution, the silica network particles comprising mainparticles having a particle size greater than a first particle size andbridging particles having a particle size less than the first particlesize, the bridging particles forming chains between adjacent mainparticles.
 9. The method of claim 1 wherein: step (e) comprisescirculating an aerated portion of the solution through a helical coilaround vertical columns of evenly spaced magnets creating an alternatingmagnetic field.
 10. The method of claim 1 wherein: step (f) comprisesrepeating steps (d) and (e) a plurality of times until silica networkparticles are formed in the solution, the silica network particleshaving a particle size greater than or equal to 1000 nanometers.
 11. Themethod of claim 1 wherein: step (f) comprises repeating steps (d) and(e) a plurality of times until silica network particles are formed inthe solution, the silica network particles having a particle sizegreater than or equal to 3000 nanometers, and the silica networkparticles comprising main particles and bridging particles formingchains between adjacent main particles.
 12. The method of claim 1wherein: step (f) comprises repeating steps (d) and (e) a plurality oftimes until silica network particles are formed in the solution, thesilica network particles comprising main particles and bridgingparticles forming chains between adjacent main particles, the mainparticles and the bridging particles having a substantially spheroidshape.
 13. The method of claim 1 wherein: step (e) comprises repeatingsteps (d) and (e) a plurality of times until silica network particlesare formed in the solution and the solution is capable of wetting ahydrophobic substrate more than pure liquid water.
 14. The method ofclaim 1 wherein: step (f) comprises repeating steps (d) and (e) aplurality of times until silica network particles are formed in thesolution and the solution has a carbonate concentration of about 4 toabout 8 millimoles per liter.
 15. An apparatus for generating silicanetwork particles in water, the apparatus comprising: a mixing vesselfor holding a silicate solution; a mixer for agitating the silicatesolution, the mixer being located In the mixing vessel; a magnetic fieldgenerating unit including a plurality of spaced apart magnets and tubingcoiled around the magnets; and a solution circulation system forcirculating the silicate solution from the mixing vessel through thetubing and back to the mixing vessel.
 16. The apparatus of claim 15wherein: the solution circulation system comprises a pump having aninlet and an outlet, a first conduit in fluid communication with theinlet of the pump and the mixing vessel; a second conduit in fluidcommunication with the outlet of the pump and an intake end of thetubing; and a third conduit in fluid communication with an output end ofthe tubing and the mixing vessel.
 17. The apparatus of claim 15 wherein:the magnets are arranged such that the poles of adjacent magnets face inopposite directions.
 18. The apparatus of claim 15 wherein: the magneticfield strength is approximately 1000 Gauss at a pole face of eachmagnet.
 19. The apparatus of claim 15 wherein: the mixer comprises amotor, a shaft mechanically coupled to the motor, and a shearing bladeattached to the shaft for agitating the silicate solution.
 20. Theapparatus of claim 15 wherein: the magnetic field generating unitfurther comprises a cylindrical drum made from a ferromagnetic material,and the magnets are positioned along an inner surface of the cylindricaldrum and the tubing encircles an outer surface of the cylindrical drum.21. The apparatus of claim 20 wherein: the magnets are vertical columnsevenly spaced along the inner surface of the cylindrical drum.
 22. Theapparatus of claim 21 wherein: the magnetic field generating unitfurther comprises a plurality of non-magnetic columns positioned betweenthe magnets.
 23. The apparatus of claim 21 wherein: the tubing of themagnetic field generating unit is coiled around the magnets such thatthe direction of solution flow is substantially perpendicular to thevertical columns of magnets.
 24. The apparatus of claim 20 wherein: themagnetic field generating unit further comprises an outer cylindricaldrum made from a ferromagnetic material, and a second group of magnetspositioned along an inner surface of the outer cylindrical drum andoutside the tubing.
 25. A method of generating silica network particlesin water, the method comprising the steps of: (a) dissolving sodiumsilicate in water to form a solution; (b) agitating the solution; (c)thereafter circulating the solution through an alternating magneticfield greater than the earth's magnetic field; (d) thereafter agitatingthe solution; (e) thereafter circulating the solution through thealternating magnetic field; and (f) repeating steps (d) and (e) aplurality of times until silica network particles are formed in thesolution, wherein step (b) comprises agitating the solution in anopen-air mixing chamber until the solution absorbs sufficient carbondioxide to lower the pH to between about 9.5 and about 10.5.
 26. Amethod of generating silica network particles in water, the methodcomprising the steps of: (a) dissolving sodium silicate in water to forma solution; (b) agitating the solution, (c) thereafter circulating thesolution through an alternating magnetic field greater than the earth'smagnetic field; (d) thereafter agitating the solution; (e) thereaftercirculating the solution through the alternating magnetic field; and (f)repeating steps (d) and (e) a plurality of times until silica networkparticles are formed in the solution, wherein step (f) comprisesrepeating steps (d) and (e) a plurality of times until the solutionabsorbs sufficient carbon dioxide to lower the pH to between about 8.5and about 9.6.
 27. A method of generating silica network particles inwater, the method comprising the steps of: (a) dissolving sodiumsilicate in water to form a solution; (b) agitating the solution; (c)thereafter circulating the solution through an alternating magneticfield greater than the earth's magnetic field; (d) thereafter agitatingthe solution; (e) thereafter circulating the solution through thealternating magnetic field; and (f) repeating steps (d) and (e) aplurality of times until silica network particles are formed in thesolution, wherein step (f) comprises repeating steps (d) and (e) aplurality of times until silica network particles are formed in thesolution, the silica network particles having a particle size greaterthan or equal to 1000 nanometers.
 28. A method of generating silicanetwork particles in water, the method comprising the steps of: (a)dissolving sodium silicate in water to form a solution; (b) agitatingthe solution; (c) thereafter circulating the solution through analternating magnetic field greater than the earth's magnetic field; (d)thereafter agitating the solution; (e) thereafter circulating thesolution through the alternating magnetic field; and (f) repeating steps(d) and (e) a plurality of times until silica network particles areformed in the solution, wherein step (f) comprises repeating steps (d)and (e) a plurality of times until silica network particles are formedin the solution, the silica network particles having a particle sizegreater than or equal to 3000 nanometers, and the silica networkparticles comprising main particles and bridging particles formingchains between adjacent main particles.
 29. A method of generatingsilica network particles in water, the method comprising the steps of:(a) dissolving sodium silicate in water to form a solution; (b)agitating the solution; (c) thereafter circulating the solution throughan alternating magnetic field greater than the earth's magnetic field;(d) thereafter agitating the solution; (e) thereafter circulating thesolution through the alternating magnetic field; and (f) repeating steps(d) and (e) a plurality of times until silica network particles areformed in the solution, wherein step (f) comprises repeating steps (d)and (e) a plurality of times until silica network particles are formedin the solution and the solution has a carbonate concentration of about4 to about 8 millimoles per liter.